Bioavailability of atrazine, pyrene and benzo[a]pyrene in European river waters

Thirteen river waters and one humic lake water were characterized. The effe cts of dissolved organic matter (DOM) on the bioavailability of atrazine, p yrene and benzo[a]pyrene (B[a]P) was evaluated. Binding of the chemicals by DOM was analyzed with the equilibrium dialysis technique. For each of the water samples, 24 h bioconcentration factors (BCFs) of the chemicals were m easured in Daphnia magna. The relationship between DOM and other water char acteristics (including conductivity, water hardness and pH), and bioavailab ility of the chemicals was studied by performing several statistical analys es, including multiple regression analyses, to determine how much of the va riation of BCF values could be explained by the quantity and quality of DOM . The bioavailability of atrazine was not affected by DOM or any other wate r characteristics. Although equilibrium dialysis showed binding of pyrene t o DOM, the bioavailability of pyrene was not significantly affected by DOM. The bioavailability of B[a]P was significantly affected by both the qualit y and quantity of DOM. Multiple regression analyses, using the quality (ABS (270) and HbA%) and quantity of DOM as variables, explained up to 70% of th e variation in BCF of B[a]P in the waters studied. (C) 2001 Elsevier Scienc e Ltd. All rights reserved.